1. Field of the Invention
The present invention relates to an apparatus for the rapid and essentially uniform heating of a food product, and more particularly pertains to a heating oven utilizing a novel heat generating system for the generating of a heated gaseous fluid medium, such as steam for the rapid heating or cooking of food, and wherein the apparatus is adapted for home and/or commercial utilizations. Moreover, the invention also relates to a method for the rapid and uniform heating or cooking of a food product through the intermediary of heated steam employing the inventive apparatus.
In many instances, when it is desired to effectuate the rapid and uniform heating and/or cooking of a food product, for example, in establishments or restaurants, in effect, those of the so-called "fast-food" genre, it is necessary, due to reasons of economics, that the food product be heated within the shortest period of time in order to obtain a quick turnover in the serving of the customers. For example, in fast-food restaurants serving pizza, wherein the lower pizza pastry layers or shells may have been precooked, and are covered with the tomato sauce, spices, and onto which a top layer of cheese has been applied, it is important that the pizza be heated and the cheese layer be melted as rapidly as possible while imparting uniform surface heating thereto, so as to produce a product which is of an appetizing and attractive appearance to a customer. Although numerous types of heating and/or cooking appliances and ovens have been proposed in order to provide the desired results, none of these have proven themselves to be satisfactory in providing an inexpensive and satisfactorily generating apparatus which will impart the required uniform degree of heating to the food product within a suitably short time frame so as not to only produce an appropriately cooked or heated food product of a highly aesthetic appeal to a customer, but which will also meet requirements for quick service, particularly in the high-volume turnover encountered in the fast-food industry. Additionally, it is of importance that the apparatus be simple to operate and service by relatively unskilled personnel, while necessitating only a moderate financial investment rendering it highly economical, while satisfying the above-mentioned criteria in the heating and/or cooking of the food product.
Essentially, the inventive heating apparatus, which is particularly designed for the rapid and substantially uniform heating of a food product, such as pizza or the like, contemplates the provision of an enclosure in the form of a cabinet which, pursuant to a preferred embodiment of the invention, incorporates two separate heating units and steam cookers in a side-by-side arrangement which, based upon need, may be operated either singly or concurrently. Each unit includes a lower cooking chamber into the bottom region of which there is introduced a suitable tray arrangement on which the food product is supported; and wherein a partition wall structure bounding the upper region of the lower cooking chamber forms a component of the unique steam generating device of the present invention. Basically, the partition wall structure separating the upper and lower chambers within each unit in the enclosure, may be constituted of a metal or metal alloy casting of high thermal conductivity within which there is integrally cast or embedded a suitable, preferably insulated electrical heating coil for raising the partition wall structure to a predetermined elevated temperature. A perforated water tube which is connected to an external water supply source, such as potable tap water, is adapted to inject sprays of water into contact with the heated upper surface of the partition wall structure in the upper chamber, volatilizing the water so as immediately convert the water into heated or supercharged steam, preferably within a temperature range of about 212.degree. to 375.degree. F., or even higher. The partition wall structure is provided with a plurality of spaced vertically extending orifices through which the steam generated within the upper chamber is ejected downwardly into the lower cooking chamber, with the orifices being dimensioned and configured so as to propel the steam downwardly at some degree of velocity while concurrently diffusing the steam within the lower cooking chamber so as to uniformly heat the interior of the lower chamber. This will impart a uniform degree of heating to the surface of the food product positioned on the tray arrangement in the lower region of the lower chamber, causing the food product, and particularly the upper surface regions thereof, to be uniformly heated by the heat of the diffused steam within the lower cooking chamber, such heating being quite rapid inasmuch as steam is one of the fastest methods of imparting BTUs to a food product. A chimney, which communicates with the lower region of the lower cooking chamber within which the food product is contained, will impart a drawing effect, and cause the gaseous fluid medium constituted of the heated steam, to be continually circulated throughout the lower chamber prior to being drawn out therefrom.
Pursuant to a specific aspect of the invention, the supporting tray arrangement for the food product includes a generally horizontally oriented tray on which the food product, such as pizza, is positioned, to one end of which there is attached an upright plate member constituting a closure for an access door to the lower cooking chamber for insertion therethrough of the tray, and wherein the opening of the closure will concurrently effect the withdrawal of the tray, and the food product positioned thereon, from the lower cooking chamber as an integral unit.
2. Discussion of the Prior Art
Although numerous patents and publications are currently known in the technology pertaining to the heating and/or cooking of various types of food products, including pizzas, and wherein various of the prior art publications are directed to commercial applications adapted to the so-called "fast-food" operations, none of these provide for the extremely rapid and efficient uniform heating and/or cooking of a food product through the utilization of heated steam with minimum expenditures of energy and at a enhanced heating time rates in a manner analogous to that contemplated by the inventive heating apparatus and method.
Burke U.S. Pat. No. Re. 1,027 of Aug. 21, 1860 discloses a cooking stove incorporating an oven having the interior space thereof uniformly heated by a hot gas which is diffused therethrough. The hot gas is received through an apertured plate arranged along the upper end of the oven, and uniformly circulated about any food located in the lower region of the oven. The hot gas is then vented upwardly by being drawn out through a chimney arranged at the side of the oven and communicating with the lower end region of the oven interior. Although Burke describes the heating of the interior of an oven with a hot gas being circulated therethrough so as to uniformly heat or cook a food product contained therein by basically convection heating, there is no disclosure nor suggestion of the inventive steam generator which will cause steam to be injected and diffused throughout a lower cooking chamber containing the food product to thereby implement the rapid and uniform heating of a food product through the utilization of heated steam.
Similarly, Farber, et al. U.S. Pat. No. 3,828,760 discloses a cooking or heating oven consisting of an enclosure in which a food product is positioned within a lower chamber. Heated air is circulated in a cyclonic vortex, with the air being previously heated in an upper space above the food-containing chamber through the intermediary of heating coils and then forced downwardly by the action of an impeller or fan. There is no disclosure of a steam generator being located above the chamber containing the food product in a manner analogous to that of the invention, and in which heated steam is employed to heat the food product in a rapid and uniform manner, with steam being a gaseous fluid medium through which BTUs can be introduced into a product so as to thereby optimize shortening the time frame for heating the product to the desired extent.
Brown, et al. U.S. Pat. No. 4,377,109 discloses an apparatus for baking a food product, such as pizzas and the like, wherein the pizzas are transported through a heating oven on a continually moving conveyor and wherein jets of heated air are circulated so as to impinge at a relatively low velocity against the surfaces, and particularly the top surfaces of the food product as it is conducted through the heating oven. There is no disclosure of a steam generator arranged above a lower chamber in which a food product, such as pizzas, is positioned in a stationary manner, and whereby jets of steam are injected into the lower chamber so as to be diffused therein and to uniformly heat the chamber to thereby heat the pizza and distribute the heat uniformly across the surface of the food, for instance, in order to uniformly melt top layers of cheese and the like on the pizza.
Perry, et al. U.S. Pat. No. 3,384,068 discloses a warming or cooking oven utilizing a gas system for circulating a flow of heated gas which is placed into motion through the use of a blower or impeller to thereby circulate about the food product in the heating chamber of the oven. There is no disclosure nor suggestion of a steam generator which is employed to provide an environment of heated steam for rapidly and uniformly heating a food product, such as pizza, positioned in the lower chamber of the heating apparatus or oven.
The rapid heating or cooking of different types of food products, such as pizza or the like, which is adapted for fast-food operations and enterprises, is also described in various patents issued to Donald P. Smith, of which U.S. Pat. No. 4,409,453 may be considered to be representative of the state of the art, having specific reference to Figures VII and VIII and the description in the specification relative thereto in that patent. In that instance, vertically downwardly directed jets of a heated gaseous fluid, such as air or the like, are directed at high velocity from a plenum through a series of orifices so as to vertically impinge against and circulate about a food product which is conveyed past the heated fluid jets while oriented normally thereof. The apparatus and method described in the various Donald P. Smith patents does not disclose the utilization of heated steam for uniformly heating a chamber containing a food product, nor the provision of a novel steam generator for generating the steam and thereafter diffusing the steam in the chamber in which the food product is contained, rather than directly impinging against the food product, so as to thereby avoid the formation of so-called "burn" spots or inadequately heated zones on the food product being heated or cooked. Consequently, the Smith U.S. Pat. No. 4,409,453, and the other interrelated Smith patents, among which U.S. Pat. Nos. 4,462,383; 4,479,776; and 4,338,901 are of general interest, all fail to describe the particular inventive apparatus incorporating a steam generator and the diffused heat system produced thereby for rapidly and uniformly heating a food product, such as pizzas, in a manner as contemplated by the present invention.